One not present (8)
I believe the answer is:
absentee
'one not present' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for absentee that I've seen before include "One is not present when required" , "One away from work, etc" , "one's failed to show up" , "One who stays away" , "to prompt a hearty increase in affection!" .)